Pressure-control system



June 30, 1925.

1543.841 |+J.GmsoLBT PRESSURE CONTROL SYSTEM Filed July 2, 1923 2Sheets-Sheet 1 Hear JEr'z'g 07272- fim'wg.

June 30, 1925.

1,543,841 H. J. GRIGQLEIT PRES SURE CONTROL SYSTEM Filed July 2, 1923 2Sheets-Sheet 2 n is R Patented June 30, 1925.

UNITED STATES 1,543,841 PATENT OFFICE.

HENRY J. GBIGOLEIT, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGGSWITCHBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINOIS PRESSURE- CONTROL SYSTEM.

Application filed July 2,

To all whom it may concern:

Be it known that I, HENRY J. Gmeonnrr, a citizen of the United States ofAmerica, residing at Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Im rovements in Pressure-Control Systems, 0 which the following 18 as ecification.

y invention relates to pressure feed systems and has more particularlyto do wlth systems in which fluid under a plurality of dilferentpressures is fed to one or more presses or hydraulic devices for formingmoulded ob'ects.

In moul ing systems, a moulding compound is placed in moulds or dieswhlch are glaced in presses and then subjected to hyraulic pressure ofdifi'erent values to form the moulding compound into the desired shapesand objects. In hot moulding, it is customary to apply a relatively lowpressure to closethe halves of the mould and then, at a pre-determinedtime, a higher pressure is applied to further press or form the compoundinto the desired shape. sired time steam is up 7 lied to the mould toheat the compound, t en subsequentl the steam is disconnected from themoul and in some instances, a cooling fluid, such as water, is appliedto the mould to cool the moulded compound. In cold moulding, the mouldis not eated by steam.

.In the prior art system, it was customary to ifovide one pump to forcethe fluid into a big prasure accumulator, and a second pump to force thefluid into the low pressure accumulator or tank. Thepumps were of thenecessary capacity to maintain the accumulators substantially filledwhen all of the presses in the s stem were in use. It is at onceapparent t at with such systems it was necessary to automaticallyconnect the pumps to the accumulators when the pressure in theaccumulators dropped and to automatically disconnect the pumps from theaccumulators when the pressure in the same raised to the desired valves.Disconnecting the high pressure pum from the high ressure accumulator anreconnecting t e pump to the accumulator caused eat strains to be thrownupon the hig pressure pump which necessitated the continuous replacingand repairing of parts of the high tpressure pump due to these suddenstrains at were placed upon At the de-' 1923. Serial No. 649,185.

the same by the automatic mechanism which connected and disconnectedthepump from the accumulator.

One object of my invention is to arrange mechanism so that one ump willnot only supply the fluid to the igh pressure accumulator, but also tothelow pressure accumulator. With this arrangement, I maintain aconstant pressure in the high pressure accumulator and then instead ofdlsconnecting the pump from the high pressure accumulator, it isautomatically connected to the low pressure accumulator. The backpressure on the pump, is maintained at substantially a constant pressuresoflthat the'pump at all times is operating against substantially aconstant pressure, thus obviating the sudden strains thrown upon thepump in the prior systems. 7

A further feature'of my invention is the means by which the .pumpingpressure applied to both, the high pressure and the low pressureaccumulators is maintained sub stantially constant whether theseaccumulators are completely filled, in which event the fluid isby-passed to a supply or surge tank or whether the accumulators arereceiving a supply from the pump. By the use of only one pump, it isreadily apparent that I greatly reduce the horsepower required tomaintain the fluid in the accumulators up to the desired pro-determinedpressures.

A further feature resides in the novel valve construction which Iemployed to maintain the accumulators at the desired pressures whileby-passin the fluid from one accumulator to the ot er and from the otheraccumulator to the reservoir tank, when the accumulators are filled. Nowwith pressures that run. up to three or four thousand pounds per uareinch, the force of the fluid very quic 1y cuts into the valve and valveseats of the prior valves'so that the valves become leaky. I havedevised'a valve which has substantially number of valve seats so thatthe extremely high pressures do not cut into my valve meichanism as wasthe case with the prior art va ves.

A further feature of my invention resides ms an infinite ythe'ue highpressure accumulator, I adjust the smaller valve so that it is artlyopen at all times, by-passin part of t e fluid to the low pressure tank.liven with this valve partly open and the fluidcontinuously surging trough this opening, I am unable to find any noticeable wear or cuttingon this valve after long usage. This may be due to the fact that thevalve wall is kept continuously rotating as the fluid passes through.

A further feature of my. invention is the provision of a plurality ofcooperating control arms for my valve mechanism which permits a minutemovement of the valve controlling plungers for large movements of thevalve controlling rods, which rods are connected to the accumulatortanks.

The above features of my invention as well as others will be more fullypointed out and described in the ensuing specification and in theappended claims.

For a more complete understanding of my invention, reference may be hadto the accompanying drawings in which like reference characters in thedifferent views denote like parts and in which:

Figure 1, diagrammatically represents my pressure feed system,

Figure 2, is a, side elevation showing one of my valves and its controlarts and,

Figure 3, is a sectional view along line 3-3 of Figure 2. a

. Referring first to Figure 1 which diagrammatically represents mypressure feed system, 2, represents the pressure pump which pum s thepressure from the supply tank 3 to t e high pressure accumulator 4 andto the low pressure accumulator 5. The pulley wheel 6 of the pump 2 isdriven by a motor not shown.

At 7, I diagrammatically represent one of the moulding presses. While Ihave only shown the high and low pressure supply pipes connected to thispress, it is to be understood that the necessary steam, air and otherconnections ai'e connected to the devices,'so that they may performtheir proper unctions Referring to the accumulator 4, this comprises apipe or reservoir 8 into which the fluid is pumped against the Weights 9which rise as the amount of fluid in the pi e 8 is increased.- Guiderods 11 are provi ed for the accumulator 4 to direct its. upward anddownward movement. The accumulator is substantially the same as theaccumulator 4 and has a pipe tank 12, which after it is filled causesthe weighted'body portion 13 to rise. I

At 14, I represent one of my double valve mechanisms which is more fullyillustrated in Figures 2 and 3. The valve mechanism is controlled bya.rod 15 which loosely fits through an orifice 16 in a plate 17 attachedto the top of the a cumulator 4.

A nut or blocking device 18 is attached to the rod 15 so that when theaccumulator reaches a pre-determined height, the valve rod 15 isoperated to operate the mechanism of the valve 14. The valve 19 and itscontrol rod 20 is substantially the same as valve 14 and its controlrod.

Pipe 21 is the high pressure supply lead to difierent presses, only oneof which is shown.

The ipe 22 is the low pressure supply line to the ifi'erent presses.

22', 23, 24 and 25 represent ordinary check valves which permit the flowof fluid in one direction only.

26 and 27 represent leaky check valves which permit a. free flow offluid in one direction and a slow flow of fluid in the oppositedirection. These check valves may be the re lar check valves with asmall hole drille through the ball check.

The outlet pipe 28 from the pump 2 is connected through the leaky checkvalve 26 to the accumulator 4, to the valve 14, and through the checkvalve 22 to the supply line 21. The by-pass outlet of the valve 14 isconnected through check valve 23 to the valve 19, also through a checkvalve 24 to the supply line 22, and also through the leaky check valve27 to the accumulator 5.

, The by-pass outlet of the valve 19 is connected back through a checkvalve 25 to the surge tank 3. Surge tank 3 is connected through pipe 30'to the pump 2.

Referring now more particularly to the valve mechanism as shown in Figs.2 and 3, it comprises a block 31 through which extends laterally anorifice 32. In one end of the orifice is a plug 34, while the other endof the orifice is threaded to receive a pipe connection. Extendingvertically into the block are the orifices 35 and 36. A secondlongitudinal orifice 37 is provided which intersects orifices 35 and 36.A plug 38 fits into one end of orifice 37. At right angles to orifice 37is an orifice 39 which intersects orifice 37 and forms a by-pass for thefluid when the valves are open. It will be noted that the opening 40extending from the orifice 35 into orifice 32 is smaller than theopening 41 which connects orifice 36 with orifice 32. Fittin intoorifice 35 is a valve seat member 43 w ich is provided with an orificethat has a slightly chamfered opening for the valve, ball To hold thevalve seat 43 in position a plug 45 is provided which has screw-threadedenga ement with threads inthe orifice 35. A pac 'ng ring 46 is providedwhich holds the packing 47 in position to prevent leakage between theplug 45 and the block 31. Extending vertically in the plug 45 is anorifice 48 through which extends the valve control rod 49. A packing rin50 is provided to hold the packing 51 m p t p t leak ge bet een the rod49 and the plug 45. The rod 49 contacts against the valve ball 44 anddepresses the same when the valve is to be opened to permit a flow fromorifice 32 through orifice into by-pass opening 39. The plu is providedwith several radially exten ing orifices 52 that open into the orifice37.

The construction of the larger valve mechanism at the right of F ig. 3is substantially the same as the construction of the smaller valvemechanism at the left of Fig. 3.

Attached to the side of the block 31 is an arm 56. Pivotally secured tothe arm 56 is a valve controlling yoke 57 and pivotally secured to thevalve controlling yoke 57 is a pair of U-shaped dependent members 58,the one member connecting to valve rod 49, and the other member to valverod 55. Valve rods 49 and are threaded and have screw threadedengagement with U-shaped members 58. Lock nuts 59 are provided formaintaining the valve rods 49 and 55 in their adjusted positions.

From the drawings it Will be noted that the smaller valve at the left ofFig. 3 is adjusted to be opened before the larger valve is opened at theright of Figure 3. The smaller valve of valve 14 is adjusted so that itis always partially opened to permit a flow from the pump 2 to theaccumulator 5, even though the main flow is into the accumulator 4.Pivotallv secured to the arm 56 is a pair of rearwardly extending arms60. Pivotally secured to the arms 60 at 61 is a rear- \vardly extendingyoke 62. An arm 64 is provided that is pivotally secured to arm 62 at65, and to the base 66 at 67. Extending cross-wise of 62 is a pin 68which is adapted to receive the forked end of the yoke 57. When the leftend of the arms 60 (which are connected together at this point) areraised they turn about their pivot pin 70 and raise the right end ofyoke 62 which is pivoted at 61 to the lever 60 and at to the lever 64.The raising of the right end of the lever 62 naturally raises its pivotpin 68 which causes the free end of the yoke 57, to be raised, therebycausing it to be turned about its pivot point 70, causing the right endof the yoke 57 to be lowered, thus forcing the U- shaped members 58downwardly, to which are attached the valve rods 49 and 55. The loweringof the valve rods 49 and 55 depresses the valve balls 4% and 75, thevalve hall 44 first. to open the passageway from orifice 32 through toby-pass opening 39. \Vhen the right hand end lever 60 is lowered, itcauses the yoke 62 to be lowered which lowers the right end of yoke 57.causing the raising of U-shaped pieces 58, thereby permitting the valvehalls 44 and 75 to seat in their valve seats. cutting off the flow ofliquid to the by-pass 39.

From the foregoing it is apparent that the valve balls 44 and 75 may beadjusted to operate in any desired sequence, and they may be made toopen at any desired position of the lever arms 60, or they may beadjusted to remain partly open when the lever 60 is in its upper-mostposition.

Returning now to Figure 1 of the drawings, when the pump 2 is started inoperation, it pumps fluid through the pipe 28 and the leaky check valve26 into the water column 8 which causes the accumulator to be raiseduntil the valve control rod 15, which is attached to the lever 60, israised a suilicient amount to open the ball valves of valve 14. As abovementioned, the high pressure feed line extends directly from the pipe28, which is connected to the pump, through the check valve 22' to thepresses. The left hand ball valve of valve 14 being partially opened,even though the accumulator 4 is not in its upper position, part of thefluid pumped by pump 2 extends through check valves 23 and 24 "to thelow pressure line 22, and through the leaky check valve 27 to theaccumulator 5 to supply liquid to the accumulator 5. Although this valveis slightly opened, the back pressure in the high pressure feed line andinto the accumulator 4 is maintained at the desired amount. When theaccumulator 4 has been raised to a certain position, the valve balls areopened an amount suflicient to permit a flow of the liquid through checkvalve 23 to the low pressure feed line 22 and to the accumulator 5, butthese openings are such as to maintain a back pressure of the desiredamount in the accumulator 4. As liquid is used from accumulator 4, it islowered and valve 14 is caused to again force the liquid intoaccumulator 4. Assuming that liquid is not being taken from accumulator4, and the liquid is being by-passed through valve 14 into accumulator5, this accumulator is raised to a osition Where it opens its valve 19to permit the by-passing of the liquid through check valve 25 to thesurge tank, but valve 19 is not opened a sufficient amount to permit thelowering of the pressure between the valve 19 and 14 below thepredetermined desired pressure.

From the above it is obvious that the pressure between the pump 2 andvalve 14 is maintained at the predetermined high pressure point, and thepressure between valves 14 and 19 is maintained at the desired lowpressure. The check valve 22' prevents a surge back from the pipe line21 into the pipe line 28, and the check valve 24 prevents a sur e backfrom pipe line 22 into the pi e 80. he leaky check valve 26 preventstlie sudden dropplng of accumulator 4 if a great number of presses areoperatively connected to the pipe line 21 at the same time, while theleaky check valve 27 prevents the sudden dropping of accumulator 5 if agreat number of presses are simultaneously operatively connected to pipeline 22.

From the foregoing it is thus obvious that as liquid is taken from pipeline 21, the pump and valve 14 will maintain the pressure 1n the pi eline 21 at substantially the predetermined value. The pump will also, inconjunction with the accumulator 5 and valve 19, maintain the pressurein pipe 22 at substantially the predetermined value. These valves willoperate to automatically prevent the accumulators from dropping to theirlowermost positions, when the resses are in use, and will by-pass theliqui from the pump 2 to the sur e tank 3 if the normal use of theliquid t rough pipes 21 and 22 falls below the output 0 the'pump 2.

While I have only shown the accumulators 4 and 5, press 7, and pump 2 indiagrammatic form, these pieces of apparatus are well known in the artand their functions are well understood. The pressures maintained byaccumulators 4 and 5 may be set at any desired points by the weightsattached to these accumulators. By adjusting the length of the rods 15and 20, the positions at which these rods will operate valves 14 and 19,may be controlled;

My system is entirely automatic and no matter how many resses may hesuddenly turned on or ofl, t e valves will cause the accumulators tosubstantially maintain the pressures at the desired values. A suddenusage of a number of presses will cause the accumulators to drop aslight amount, still the pressures will be maintained at the desiredvalues, and the pump will again restore the accumulators to their upperposi-v tions before the ressures drop elow the desired predeterminedamounts in the pipes 21 and 22.

While I have illustrated only one form of my invention, I do not wish tobe limited to the exact arrangement as shown, as various otherarrangements may readily suggest themselves to those skilled in the art,and I, therefore, aim to cover all such changes and modifications ascome within the spirit and scotpee of the appended claims.

Having descri d my invention what I claim as new and desire to secure byLetters Patents is:-

1. A fluid su ply system of the character described inclu mg a pair ofaccumulators, a pump for supplying liquid to said accumulators, andautomatic means for connecting said pump to said accumulators to main-'tam the desired predetermined pressures in each of said accumulators.

2. A system of the character described including a pair of accumulatorsadapted to supply fluid at predetermined pressures, a pump for supplyinga fluid to said accumuators, and automatic means controlling theconnection of said ump to said accumulators to maintain t apredetermined pressures in each of said accumulators.

3. A fluid feed system of the character described including a pair ofaccumulators, a pump for supplying fluid to said accumulators, automaticmeans for controlling the supply of fluid from said pump to one of saidaccumulators to maintain the desired predetermined pressure in saidaccumulator, and a second automatic device for controlling the supply offluid from said pump to the other of said accumulators to maintain thepredetermined desired pressure in said second accumulator.

4. A fluid feed system of the character described including a pair ofaccumulators, a pump for supplying fluid to said accumulators, automaticmeans for controlling the supply of fluid from said pump to one of saidaccumulators to maintain the desired predetermined pressure in saidaccumulator, a second automatic device for controlling the supply offluid from said pump to the other of said accumulators to maintain thepredetermined desired pressure in said second accumulator, and a storagetank adapted to receive the excess fluid from said pump, said secondautomatic device controlling the supply of the excess fluid to saidstorage tan 5. A fluid control system of the character describedincluding a relatively high pressureaccumulator, a relatively lowpressure accumulator, a single ump for supplying fluid to these accumuators, and an automatic valve for said first accumulator for regulatingthe flow of fluid from said pump to said accumulator to maintain arelatively constant pressure in said first accumulator and for supplyingthe excess fluid from said pump to said second accumulator.

6. A fluid control system of the character described including arelatively high pressure accumulator, a relatively low pressureaccumulator, a single pump for supplying fluid to these accumulators,and an automatic valve for said first accumulator for regulat ing theflow of fluid from said ump to said accumulator to maintain a re ativelyconstant pressurein said first accumulator and for supplying the excessfluid from said pump .to said second accumulator, a storage tank, and asecond valve for controlling the supply of fluid from said first valveto said second accumulator to substantially maintain a predeterminedpressure in said secondaccumulator.

7. A fluid control system of the character described including arelatively high pressure accumulator, a relatively low pressureaccumulator, a single ump for supplying fluid to these accumu ators, andan automatic valve for said first accumulator for regulating the flow offluid from said pump to said accumulator to maintain a relativelyconstant pressure in said first accumulator and for supplying the excessfluid from said pump to said second accumulator, a storage tank, and asecond valve for controlling the suppl of fluid from said first valve tosaid secon accumulator to substantially maintain the predeterminedpressure in said second accumulator, said second valve controlling theexcess flow of fluid from said pump to said storage tank.

8. A system of the character described including a relatively highpressure accumulator and a relatively low pressure accumulator, a pumpfor supplying fluid to said accumulator, an automatic valve forcontrolling the flow of fluid from said pump to said first accumulatormaintaining the pressure in the first accumulator at the predetermineddesired point, and a second valve controlling the flow of fluid intosaid second accumulator thereby maintaining the pressure in the secondaccumulator at the predetermined desired point.

9. A system of the character described including a relatively highpressure accumulator and a relatively low pressure accumulator, a pumpfor supplying fluids to said accumulator, an automatic valve forcontrolling the flow of fluid from said pump to said first accumulatormaintaining the pressure in the first accumulator at the predetermineddesired point, a second valve controlling the flow of fluid into saidsecond accumulator thereby maintaining the pressure in the secondaccumulator at the predetermined desired point, and a storage tank, saidsecond valve directing the excess flow of fluid from said pump to saidstorage tank.

10. A system of the character described including an accumulator, asurge tank, a pump for supplying fluid to said accumulator, an automaticvalve for controlling the supply of fluid from said pump to saidaccumulator substantially maintaining a predetermined pressure in saidaccumulator and maintaining substantially the same back pressure uponsaid pump even though the fluid is being by-passed through said valve tosaid surge tank.

11. A fluid control system of the charac ter described including anaccumulator, a surge tank, a pump for supplying fluid to saidaccumulator, an automatic device controlled by said accumulator fordirecting the supply of fluid from said pump thereby maintaining asubstantially predetermined pressure in said accumulator and by-passingthe excess flow that is not used by said accumulator to said surge tankbut maintaining the back pressure upon said pump substantially equal tothe pressure maintained in said accumulator.

12. A pressure control system of the character described including anaccumulator, a

ump for supplying fluid to said accumuator, a supply line leadin fromsaid accumulator, and an automatic device including a pair ofoperatively associated automatic valves for maintainm the pressure insaid accumulator and supp y ipe and the back pressure on said pump sustantially at the predetermined desired point.

13. A pressure control system of the character described includin anaccumulator, a pump for supplying fluid to said accumulator, a supplyline leading from said accumulator, an automatic device for maintainingthe pressure in said accumulator and supply pipe and the back pressureon said pump substantially at the predetermined desired point, a secondaccumulator, a second supply line, and a second automatic device formaintaining the pressure in said second accumulator and supply line andthe back pressure between said first valve and second valvesubstantially at a predetermined desired point.

14. A pressure control system of the character described including anaccumulator, a pump for supplyin fluid to said accumulator, a supplyline deading from said accumulator, an automatic device for maintainingthe pressure in said accumulator and supply pi e and the back pressureon said pump su stantially at the predetermined desired point, a secondaccumulator, a second supply line, and a second automatic device formaintaining the pressure in said second accumulator and supply line andthe back pressure between said first valve and second valvesubstantially at a predetermined desired point, and a reservoir. adaptedto receive the excess fluid from said pump.

15. A pressure supply system of the character described including aplurality of accumulators, a pump for supplying said accumulators withfluid, an automatic valve having a normal opening permitting a portionof the fluid being pumped to by-pass around one of said accumulators toanother of said accumulators, said valve maintaining the pressure insaid first accumulator at the predetermined desired pressure and subseuently operating to increase the flow of fluid to said secondaccumulator.

16. A pressure feed system of the character described including a pairof accumulators, a pump for supplying fluid to said accumulators, anautomatic valve normally permitting a small flovv of fluid from saidpump to said second accumulator while maintaining the pressure in saidfirst accumulator at the predetermined desired point.

17. A ressure feed system of the character described including a pair ofaccumulators, a pump for supplying fluid to said accumulators, anautomatic valve normally permitting a small flow of fluid from said pumpto said second accumulator while maintaining the pressure in said firstaccumulator at the predetermined desired Ill point, said valve adaptedto permit a larger flow of fluid from said pump to said secondaccumulator by an action controlled by the first accumulator.

18. A pressure feed system of the character described including a pairof accumulators, a pump for supplying fluid to said accumulators, anautomatic valve normally permitting a small flow of fluid from said pumpto said' second accumulator while maintaining the pressure in said firstaccumulator at the predetermined desired point, said valve adapted topermit a larger flow of fluid from said pumpto said second accumulatorby an action controlled by the first accumulator, a return tank, and asecond automatic device for directing any excess flow of fluid to thesaid return tank.

19. A pressure feed system of the character described including a air ofaccumulators, a pump for supplying fluid to said accumulators, anautomatic valve normally Y permitting a small flow of fluid from saidpump to said second accumulator while maintaining the pressure in saidfirst accumulator at the predetermined desired point, said valve adaptedto permit a larger flow of fluid from said pump to said secondaccumulator-by an action controlled by the first accumulator, a returntank, and a second automatic device for directing any excess flow offluid to the said return tank,

said first valve maintaining the back pressure upon the pump atsubstantially the pressure maintained in said first accumulator and saidsecond valve substantially maintaining the pressure between the saidfirst valve and said second valve at the pressure maintained in saidsecond accumulator.

20. A pressure feed system of the character described including arelatively high pressure accumulator and a relatively low presureaccumulator, a pump for supplying fluids to said accumulators, andautomatic means for maintainin the ressures in said accumulators at theesire predetermined point.

21. A pressure feed system of the character described including arelatively high pressure accumulator and a relatively low pressureaccumulator, a pump for supplying fluid to said accumulators, andautomatic means for substantiall maintaining the pressure in said accumuators at the desired predetermined points, supply lines leading fromsaid accumulators, and means for preventing a sudden drop in thepressures maintained in said accumulators.

22. A pressure feed system of the character described including arelatively high pressure accumulator and a relatively low pressureaccumulator, a pump for supplying fluid to said accumulators, automaticmeans for substantially maintaining the pressures in said accumulatorsat the desired predetermined point, sup ly lines, and means forpreventing a bac flow from said supply lines to said accumulators.

23. A ressure feed'system of the character described including a air ofaccumulators, fluid in said accum ators adapted to be maintained atdifferent predetermined pressures, a pump for supplying fluid to saidaccumulators, and automatic means for preventing a back flow of fluidfrom said accumulators to said pump.

24. A pressure fee system of the character described including arelatively high pressure accumulator and a relatively low presureaccumulator, a pump for supplying fluid to said accumulators, andautomatic means for substantiall maintaining the pressures in saidaccumu tors at the desired predetermined point, and means for preventinga sudden change in the pressures maintained in said accumulators.

25. A ressure feed system of the character described including a pair ofaccumulators adapted to be maintained at difl'erent predeterminedpressures, a pump for en plying "fluid to said accumulators, supp ylines, and automatic means for preventing a. back flow from said supplylines to said accumulators.

26. A pressure feed systemof the character described including arelatively high pressure accumulator and a relatively low pressureaccumulator, a pump for supplying fluid to said accumulators, automaticmeans for substantially maintaining the pressures in said accumulatorsat the desired predetermined point, and means for preventing a suddenchange in the pressures maintained in said accumulators, means forpreventing a back flow from said accumulators to said pump, supplylines, and means for preventing a back flow from said supply lines tosaid accumulators.

27 A pressure feed system of the character described including arelatively high pressure accumulator and 'a relatively low pressureaccumulator, a pump for supp-lying fluid to said accumulators, automaticmeans for substantially maintaining the pressure in said accumulators atthe desired predeter- -mined point, means for preventing a sudden changein the pressures maintained in said accumulators, means for preventing aback flow from said accumulators to said pump, suppl lines, means forpreventing a back flow gom said supply lines to said accumulators, atank for receiving the excess flow of fluid from said ump, and means forpreventin a back ow of fluid from said tank to sai accumulators.

28. A fluid supply system of the character described including anaccumulator, a pump for supplying liquid to said accumulator, aconnection extending from said pump to said'accumulator, a supplyconnection extend' 'from said first connection, and a device orpermitting a ready flow of fluid from said pump to said accumulator butpermitting a less ready flow of fluid from said accumulator to saidsupply connectlon.

- 29. A supply system of the character described includmg a pair ofaccumulators, a pump for supplying fluid to said accumula- 10 tors,connections from said pump to said accumulators, a supply commotionextending from each of said accumulators and devices permitting a readyflow of fluid from said pum to said accumulators but permittin a lessready flow of fluid from sald accumu ators to said supply connections.

Signed by me at Chicago in the county of Cook and State of Illinois,this 29th day of June, 1923.

HENRY J. GRIGOLEIT.

1 tors, connections from said pump to said accumulators, a supplyconnection extending from each of said accumulators, and devicespermitting a ready flow of fluid from said pump to said accumulators butpernnttin a less ready flow of fluid from said aecumu ators to saidsupply connections.

Signed by me at Chicago in the county of Cook and State of Illinois,this 29th day of June, 1923.

HENRY J. GRIGOLEIT.

Certificate of Correction.

It is herebycer tified that Letters Patent No. 1,543,841, granted June30, 1925, upon the application of'I-Ienry J. Grigolei't, of Chicago,Illinois. for an improve- I ment in Pressure-Control Systems, wereerroneously issued to Kellogg Switchboard and SupplyCornpany, ofChicago, Illinois, a Corporation of Illinois, as asslgnees of the entireinterest in said invention, whereas said Letters Patent should have beenissued to the inventor, said Gm'golez't, as sole owner of saidinvention; and that the said Letters Patent should be read with thiscorrection therein that the same may conform to the record of the casein the Patent Oflice.

Signed and sealed this 18th day of August, A. D. 1925.

KARL FENN'ING, Acting Omflmiasiomr of Patents.

Certifieate of Correction.

It is hereby certified that Letters Patent No. 1,543,841, granted June30, 1925, upon the e plication of'Henry J. Grigoleit, of Chicago,Illinois, for an improvement in l i'essure-(fontrol Systems, wereerroneously issued to Kellogg Switchboard and Supply Company, ofChicago, Illinois, a Corporation of Illinois, as assignees of the entireinterest in said invention, whereas said Letters Patent should have beenissued to the inventor, said Grigoleit, as sole owner of said invention;and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Oflice.

Signed andsealed this 18th day of August, A. D. 1925. r,

[em] KARL FENNING,

Acting Commissioner of Patents.

